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RS - 232 Null Modem Cable

If you are using the internal clocking option of the controller card, you will require this cable. We recommend that you use an "I-E" synchronous null modem cable as an extension to the standard RS-232. The "I" end is connected to a link that is internally clocked, where we provide our transmit clock. The "E" end is connected to a device that wants externally provided clocks.

This cable also swaps Receive and Transmit Data and other EIA signals, so that it is a modem eliminator, or null modem cable. Because of this, DO NOT USE THE I-E JUST TO CONNECT TWO MALES TOGETHER.

The on-line manuals contain information on connecting two machines together without a network, using this cable.

For Direct Connection

DCE

Standard modem cable Or one leg of Y cable
I-E cable
Other X.25 DTE
Male
Female
Male
Female
Female
Male
(Provides Clocks)

 

I
E
(Accepts Clocks)

I-E Cable

"DCE"
I
E
"DTE"
Internally Clocked Clock
Provider Description
Pin Number
Externally Clocked Clock
Acceptor Description
GND, Common Signal Ground
1
1
GND, Common Signal Ground
RD, Receive Data
3
2
TD, Transmit Data
TD, Transmit Data
2
3
RD, Receive Data
CD, Carrier Detect
8
4
RTS, Request to Send
DTR, Data Terminal Ready
20
6
DSR, Data Set Ready
w
w
5
CTS, Clear to Send
GND, Common Signal Ground
7
7
GND, Common Signal Ground
RTS, Request to Send
4
8
CD, Carrier Detect
RC, Receive Clock
17
15
TC, Transmit Clock
XTC, DTE Clock
24
17
RC, Receive Clock
w
15
w
w
CTS, Clear to Send
5
20
DTR, Data Terminal Ready
DSR, Data Set Ready
6
w
w

Rx
=Receive, Tx=Transmit, CTS=Clear to Send, RTS=Ready to Send,
DTR=Data Terminal Ready, DSR=Data Set Ready, DCD=Data Carrier Detect